模拟胃液条件下抗坏血酸清除碘酸根离子的实验研究  

An experimental study on the scavenging effect of ascorbic acid on iodate ions in simulated gastric juice

作　　者：张亚平[1] 张淑琼[1] 李呐[1] Zhang Yaping Zhang Shuqiong Li Na(Department of Laboratory, Xiamen Center for Disease Control and Prevention, Xiamen 361021, China （Zhang YP, Zhang SQ, Li N)

机构地区：[1]福建省厦门市疾病预防控制中心检验科,厦门361021

出　　处：《中华地方病学杂志》2017年第3期176-181,共6页Chinese Journal of Endemiology

基　　金：厦门市医学中心/重点专科建设项目（2013）

摘　　要：目的探讨在模拟人胃液中碘酸根离子（IO3^-）被抗坏血酸（C6H8O6，即维生素C，简称VC）还原为碘离子（I^-）的转化率，为食用加碘酸钾（KIO3）碘盐安全性的进一步评价提供参考。方法建立测定模拟胃液中I^-的离子色谱分析法，以10，一被还原为I^-的转化率为清除IO3^-的指标，在体外模拟胃液条件下（37℃水浴中反应），测定VC在不同浓度、不同模拟胃液酸度和反应时间对IO3^-的清除效果。使用Dionex IonPacAS19离子色谱分析柱（250mm×4．0mm），30mmoL／L氢氧化钾（KOH，在线产生）淋洗液，等度淋洗，流速为1．0ml／min，进样体积为100μl，电导检测器检测。结果测定方法性能：在0～5000μg／L范围I^-浓度与色谱峰面积的线性关系良好（相关系数r=0．9997），I^-的检出限为20μg/L。模拟胃液中定量加I^-，6次重复测定的相对标准偏差（RSD）〈2．0％，加标回收率范围为97．6％-102．4％，总平均回收率为99．4％。在模拟胃液条件下，含VC5mg／L及≥10mg／L的pH=1．4模拟胃液，使外加入的IO3^-还原为I^-的转化率达100％的混合反应时间分别是5、2min。含VC10mg／L的pH=3模拟胃液，使该转化率达100％的混合反应时间是15min。在模拟胃液条件下，VC可按还原反应方程式的反应物计量关系定量还原IO3^-为I^-，100μgVC可定量还原24．0μg碘酸根碘为I^-。结论模拟胃液条件下，IO3^-被VC还原为I^-的反应是属于化学定量反应，并且有较快的反应速度，胃液中浓度水平的VC对化学等当量的IO3^-清除率可达100％，人在正常饮食中由食用加KIO3碘盐摄入的IO3^-，其进入人机体中被还原为I^-的过程主要是发生在人的胃中。Objective To explore the conversion rate of iodate ions （IO33 being reduced to iodide ions （I-） by ascorbic acid （C6HsQ, VC） in simulated human gastric juice, and to provide references for further safety evaluation of edible salt iodized with potassium iodate. Methods An ion chromatography method was developed to detect iodide ions in simulated gastric juice. The conversion rate of iodate ions being reduced to iodide ions was used as the index for scavenging rate of iodate ions. In simulated gastric juice in vitro and in 37 ℃ water bath, the scavenging effects of VC on iodate ions were determined in simulated gastric juice with different VC concentrations and simulated gastric juice acidities, as well as for different reaction time. Ion chromatography column： Dionex IonPac AS19 （250 mm × 4.0 mm）; eluent： KOH 30 mmol/L （online produced）, isocratic eluting, flow rate 1.0 ml/min, injection volume 100 μl, and detected by a conductivity detector. Results Performance of the method： within the range of 0 - 5 000 μg/L, iodide ions concentration and the chromatographic peak area had a good linearity （correlation coefficient r = 0.999 7）, and the detection limit of iodide ions was 20 μg/L. For quantification of iodide ions in simulated gastric juice, the relative standard deviation （RSD） of repeated measure for 6 times was 〈 2.0%, the standard addition recovery rate was 97.6% - 102.4%, and the overall average recovery rate was 99.4%. In the simulated gastric juice with a pH of 1.4 containing 5 mg/L and ≥ 10 mg/L VC, the reaction time to achieve 100% conversion rate of iodate ions being reduced to iodide ions was 5 min and 2 min, respectively. In the simulated gastric juice with a pH of 3 containing 10 mg/L ascorbic acid, the reaction time to achieve 100% conversion rate was 15 min. VC quantitatively reduced iodate ions to iodide ions by the stoichiometric relationship between reactants of the reduction reaction equation, and every 100 μg VC quantitatively reduced 24.0 μg of iodin

关 键 词：胃液 碘 盐类 碘酸根离子 抗坏血酸 转化率 清除率 

分 类 号：R333.2[医药卫生—人体生理学]